1. Field of the invention
The invention relates to a method for cleaning ballast. More particularly, the invention relates to a method for cleaning ballast of a track comprising rails extending in a longitudinal direction, said method being carried out by means of a ballast cleaning machine. The machine has a machine frame supported on on-track undercarriages and includes a cleaning chain with a chain cross member extending perpendicularly to the longitudinal direction.
The invention also relates to a machine for carrying out said method.
2. The Prior Art
An article in the the trade journal “Eisenbahningenieur” (52) 8/2001, page 81 (“New cleaning chain for ballast bed cleaning machine RM 800”) describes a method of this type. According to this method, the track has to be severed at the start of cleaning in order to be able to position a chain cross member of a special, very efficient cleaning chain of a ballast cleaning machine in the ballast bed underneath the track. A machine of this type is known, for example, from U.S. Pat. No. 5,926,981. During working operations of this machine, the machine frame is supported at each end on the track by means of a respective on-track undercarriage. According to a further version, visible in FIG. 2 of said patent disclosure, the on-track undercarriage situated in front of the cleaning chain, with regard to a working direction of the machine, can be distanced from the chain during working operations.
According to U.S. Pat. No. 4,538,687, it is known to lift an on-track undercarriage, positioned immediately ahead of the cleaning chain of a ballast cleaning machine, permanently off the track during working operations. As a result, it is possible even in this section to impart to the track a deflection curve necessary for lifting the track. The raised on-track undercarriage merely serves for mobility of the machine during transfer travel in order to be able to move or guide the machine within the track clearance profile.